Yarn twisting apparatus and method



Dec. 27, i949 vv. A. AGRESTI f-:TAL

YARN TWISTING APPARATUS AND METHOD Filed Oct. 6, 1948 wl x 3 lhwentoxsPe'teniea Dee. 21, 1949 vincent A. Anesu, nocheue Park, and George w.

Bogdanffy, Clyde 0. Mitchell, and Henry C. Uhlig, Clifton, N. J.,assignors to Howe Machinery Company, lne., Passaic,- N. J., acorporation o! NewV Jersey Application oetqber c, 194s, serial No.52,994

Claims.

1 This invention relates to an apparatus for twisting flexible elongatedmaterials composed at least largely of a plurality of continuouslilaments, such as yarn, and to a method of twisting such materials.

The invention has among its objects the provision of apparatus fortwisting yarns and the .like elongated vilexible materials, particularlythose composed at least largely of a plurality of iine continuous,substantially parallel, filaments, by which breakage of the laments as aconsequence of their passage through a tension imposing device andsubsequently into a twisting means is substantially eliminated.

A further object of the invention resides in the provision of apparatuscombining a tension imposing means and a twisting device subsequentlyoperating upon the elongated iiexible material with means interposedvbetween the tension and twisting devices to prevent travel of the twistbackwardly to the tension device.

The invention has as a still further object the provision of a method oftwisting elongated flexible materials composed at least largely of aplurality of ne, continuous, substantially parallel, laments wherein thematerial is subjected to retarding tension and is then twisted, thematerial being so manipulated between such operations that the twist isprevented from extending back to the location of imposition of thetension, whereby the illaments may realign themselves before beingtwisted together.

These and further objects of the invention will be more readilyunderstood in the following description of preferred embodiments of theapparatus and method in accordance therewith.

It is to be understood that the invention may be used to advantage invarious types of apparatus for twisting elongated flexible materialssuch as yarns, and that itis not necessarily employed in a twistingspindle, or in a twisting spindle of the 2-for-1 type with which theinvention is illustrated and described. It is also to be understoodthat, whereas the elongated flexible material with which the apparatusand method are described as being employed as rayon yarn, the materialswith which it is useful may be composed wholly or at least largely of aplurality of elongated, substantially continuous, parallel fibers ofwhatever origin, such terminology including yarns composed wholly ofsynthetic fibers such as rayon, nylon, and the like, combinations ofsuch bers, as well as yarns composed of line wires.

Prior to the present invention, in the spinning of yarns of the typedescribed. of which rayon is typical, diiliculty has been experiencedbecause the twisted threads were undesirably fuzzy. Microscopicexamination of the threads showed that the fuzz was composed of the endsof broken 'lamenta Further research into the problem revealed that thetension imposing and twisting apparatus employed subjected the yarnentering the tension device to such` forces that loops were formed insome of the laments of the yarn prior to its entry into the tensioningdevice. Such loops travelled .through the tension device and wereimmediately caught in the twisted iilaments, since twisting of the yarnbegan immediately at the exit end of the tension device. Typical loopsof the type under discussion, enlarged somewhat in size for ease ofillustration, are shown at 86 in Fig. 6 in some of the filamentscomposing the yarn 30 entering between the elements 56 and 60 of thetension device to be described.

The apparatus of the invention overcomes such diiliculty and produces athread substantially free from fuzz, that is, broken filaments, byinterposing between the tension means and the twisting device, andsubstantially spaced from the former, a twist barrier, that is, meansengaging the yarn as it issues from the tension device and preventingthe twist from extending back to the tension device. There is thusprovided a path of travel of the yarn, subsequent to the tension device.of substantial extent in which the yarn is subjected to purely tensileforces. Within such path the laments, subjected to tension by mechanismoperating upon the yarn in its forward portion, may realign themselvesso that the laments lie substantially parallel and so that whateverloops in the laments which have passed through the tension device willbe pulled out without breakage of such filaments. The twist is thenimposed upon the laments when they are free from loops and liesubstantially parallel to each other; in such condition of the yarnthere is no tendency to impose a greater tension on one lament thananother, so that practically no breakage of laments occurs upontwisting.

The invention will be more readily understood by reference to theaccompanying drawing, in which Fig. 1 is a view in axial section througha 2-for-1 twisting spindle embodying the apparatus of the invention;

Fig. 2 is an enlarged view in axial section through the tension imposingand twist barrier device shown in Fig. 1;

Fig. 3 is a view in cross section through the elongated membertensioning device.

ateatro magnet of the tension device, the section heilig taken along theline @-31 in Fig. 2;

Fig. 4 is a fragmentary view in axial section through the lower portionof a tension device incorporating another embodiment of twist barrier;

Fig. 5 is a fragmentary view in cross section through the apparatus ofFig. 4, the section being taken along the line 5-5 in Fig. 4; and

Fig. 6 is a somewhat schematic enlarged fragmentary view in sectionshowing the yarn as it passes into and through the tension device.

The apparatus of the invention, by way of illustration, is shownincorporated in a 2-for-1 twisting spindle of the type illustrated anddescribed in the patent application of Henry C. Uhlig. Serial No. 46,108led August 25, 1948, entitled Flexible The tension imposing device hereshown and described is generally similar to that disclosed and claimedin such Uhlig application. It is to be understood, however, that withinthe scope of the invention the apparatus and method may be employed incommotion with any known twisting apparatus employing a tension imposingdevice and a subsequent, adjacently positioned, yarn twisting device.

The twisting spindle shown in Fig. l is provided with a shaft 2supported for rotation in the sleeve 4 as shown, such sleeve in turnbeing supported in the membera which forms a portion of the frame of acord twisting machine (not shown). Shaft 2 is driven by the pulley 8which is designed to be engaged by a driving belt, not shown. Keyed toshaft 2 above the pulley for rotation therewith is the twisting disc I0.Above such disc and iioatingly mounted on the upper end of shaft 2 is abobbin support having a lower flanged portion I2 and an upstandingcentral tube portion I4telescoping the upper end of the shaft 2. Thebobbin or wound package I8 of yarn to be twisted is provided with a coreI6 which is mounted upon tube I4 and held centrally thereof againstrotation with respect thereto by top and bottom annular spacers, asshown. In this instance the yarn 30 of which package I8 is composed is aat yarn, that is, it is generally of rectangular cross section and ismade up of a pluraity of fine, continuous, flexible filaments or fiberslying substantially parallel to each other. The bobbin or packagesupport, and consequently the package, are mounted to floatsubstantially in one angular position by means of eccentrically mountedweight on the flange I2, the shaft 2 being mounted at a small angle tothe vertical, as for instance, 12.

Mounted on top of the bobbin support is the tension device generallydesignated 22, such device being, as stated, generally of the typedisclosed and claimed in the prior Uhlig application. Below the tensiondevice and mounted on the top of the shaft 2 so as to rotate therewithis the twisting guide 24 which engages the yarn as it passes downwardlyfrom the tension device. The

yarn is thus given a rst twist in that portion of its travel between thetension device and the twisting guide 24. Below such twisting guide theyarn travels through the axial passage 26 in shaft 2 and then throughthe radial passage 28 in the twisting disc 6, such two passages beingconnected as shown. The yarn then passes outwardly into the balloon 32,by which the yarn is subjected to tension throughout its length backwardto the tension device 22, and upwardly to a guiding eye (not shown)positioned above and coaxial with shaft 2 so that the yarn is given asecond twist in its passage through the balloon 82.'

in the embodiment of the invention shown in Mgs. l and 2 the twistbarrier interposed between the tension device and the twisting guidetakes the form of a bent yarn conducting tube 64, the bend in such tubebeing sucient markedly to divert the yarn from the straight path whichit otherwise would take between the tension device and the twistingguide, such diversion being sufcient to stop travel of the twist fromthe twisting guide at the bent portion of the tube. The structure ofthis embodiment of twist barrier and its relationship to the tensiondevice will be more clearly apparent from a consideration of Fig. 2.

As shown, the tension device and the twist barrier are, for convenience,incorporated in a single supporting member 34. Member 34, which isgenerally in the form of a right circular cylinder, has its lower end 36of reduced outer diameter, portion 36 joining the upper part of the bodyat the shoulder 38. Portion 36. as is evident in Fig. 1, is heldnon-rotatively with respect to tube I4 by being telescoped within theupper end of the tube I4 of the bobbin support, the shoulder 38 restingon top of such tube. The upper end of body 34 is in the form of anupwardly tapering frustum of a cone, the top edge 42 being rounded toguide the incoming yarn 30 smoothly into the tension device. The upperend of body 34 is provided with an axial counterbore 44 in whichis'snugly received the integral permanent magnet 46. Such magnet, whichperforms the same general function as the magnet in the tension devicedisclosed in the prior Uhlig application, and may be made of the samealloys as those disclosed in connection with such magnet in the saidUhlig application, is generally of right circular cylindrical form, asevident in Fig. 3. A transverse slot through the upper portion of themagnet makes it generally -of U cross-section, as shown in Fig. 2, thetwo upstanding legs being designated 52 and 54 and the bottom connectingportion being designated 50. An axial bore 48 is provided throughportion 50 of the magnet to allow reception of the upper, non-magnetic,yarn guiding tube 18. In this embodiment the magnet is magnetized sothat one of the upstanding portions, such as 52, is the north pole andthe other portion, such as 54, is the south pole.

Positioned in counterbore 44 above magnet 46 is the non-magneticseat-providing member 56 having the centrally located seat 5B, in theform of a portion of a sphere, provided on its upper surface. Such seatcommunicates with a central axial yarn receiving bore in member 56, asshown. A ball 60, made of magnetic material, and preferably being of thesame diameter as the sphere on which seat 58 lies, is retained in theseat through attraction exerted thereon by magnet 46. Yarn 30 passesbetween the seat 58 and the ball 60, as shown, and is subjected to aretarding tension as a result thereof. Such tension may be varied byvarying the attraction between the magnet and ball. In' the deviceshown, this is accomplished by providing a threaded mounting for member56 in the counterbore 44 so that member 56 may be raised or lowered withrespect to the magnet. Member 56 is retained in a desired predeterminedadjusted position by means of the locking means 62 which selectivelydeforms one threaded portion of seat member 56 with respect to theother.

The bent tube 64 has an upper' straight axially extending portion 66, alower straight axially extending portion 88, and an intermediate bentpora recess in the wall of counterbore 39 below member 14. Tube 64 isheld in coaxial relationship l0 with body 34 by having its upper endsnugly received in axial bore 12 in body 34. The upper cord guiding tube18 is mounted by having its lower end telescoped within the upper end ofportion 66 of the bent tube. as shown.

A consideration of the embodiment of the apparatus shown in Figs. 1 and2 will reveal that the bent portion of tube 64 is of such configurationthat, no matter how yarn 3| emerging from the tension device 22 ispresented to such tube 64, such yarn engages the inner wall of the tubeat at least three points, the upper, rst bend 8|), the intermediate bend82, and the lower, last, bend 84. Such engagement of the yarn with thewall of the tube, in conjunction with the tension to which the yarn issubjected, prevents passage at least above the upper bend in the tube 64of the twist imparted to the yarn in the portion 33 of its travel abovethe twisting guide. The

yarn issuing from the tension device in that portion of its traveldesignated 3|, between such device and at least its first point ofengagement with the wall of tube 64, is subjected to a, purely tensileforce, so that the laments in the yarn may realign themselves and anyloops formed in the laments will be pulled out before the yarn issubjected to twist in its portion 33.

Although the embodiment of twist barrier shown in Figs. 1 and 2 is to bepreferred because of its simplicity, economy, and ease of threading,various other types of twist barriers may be employed within the scopeof the invention. One such other twist barrier is shown in Figs. 4 and 5in which it is incorporated in the lower end of a tension devicesupporting body similar to member 34 in Fig. 2. Such body and its partswhich correspond to those shown in Fig. 2 are designated by the samereference characters primed. In this embodiment of the device, since nobent tube is employed, the upper yarn guiding tube 88 corresponds infunction to the tube 18 previously described, is mounted directly onbody 34' at 90.

The twist barrier in this instance is composed of rollers engaging theyarn to divert it markedly from the straight line path which it wouldtake between the tension device and the twist guide in the absence ofthe twist barrier. Two such rollers are employed, the bottom rollerbeing designated 92 and the upper one 94. Such rollers are mountedwithin the counterbore 39 on axles 96 and 98, respectively, the axlesand rollers being retained in place by conventional split spring ringsengaging in grooves in the axles, such rings on axle 96 being designated|00 and those on axle 98 being designated |02. l

Yarn in the portion 3|' of its travel, after having issued from thetension device, not shown in Figs. 4 and 5, is passed first around thegroove |84 in roller 92, thence upwardly and around the groove |06 inroller 94, and finally downwardly into the engagement of short angularextent with groove |88 in roller 92, from which it emerges into the pathshown at 33'. From path 33' the yarn enters a twisting guide. not shownin Figs.

4 and 5, such as guide 24 shown in Fig. 1. The diversion of the yarnabout the guide rollers, in conjunction with the tension imposed on theyarn, is suillcient for such rollers to constitute a twist barrier,substantially no twist reaching the yarn above its engagement withgroove |84 in roller 92.

Although we have described and illustrated preferred embodiments of theapparatus for, and a method of, twisting elongated flexible materialssuch'as yarns, it is to be understood that such embodiments areillustrative only since the invention may be varied considerably as todetails. The invention is therefore defined within the scope of theappended claims.

We claim as new the following:

1. A tensioning device for yarn or the like travelling in theV directionof its length under tension imposed upon it in its forward portion,which comprises means for engaging the yarn in its travel and forimposing a substantial retarding force lthereon, and means immediatelyforward of the yarn engaging means but spaced a substantial distancetherefrom for substantially diverting the yarn issuing from the yarnengaging means from a straight line path of travel, the last named meanscomprising a member having a smoothly curved yarn receiving andconducting surface of such curvature that it substantially preventstravel/of twist in the yarn, imparted to the yarn at a locationimmediately forward of the yarn diverting means, into the span of theyarn between the vyarn engaging means and the yarn diverting means.

2. A tensioning device for yarn or the like travelling in the directionof its length under tension imposed upon it in its forward portion,which comprises a first means for engaging the yarn in its travel andfor imposing a substantial retarding force thereon, and a second meansim- -mediately forward of the iirst yarn engaging means but spaced asubstantial distance therefrom for engaging the yarn issuing from thefirst yarn engaging means, the second yarn engaging means comprising amember having a I curved yarn receiving and conducting passagetherethrough of such curvature that the yarn passing through it issubstantially diverted from a straight path of travel and so that travelof twist in the yarn, imparted to the yarn at a location forward of thecurved passage, into the span of the yarn between the first and secondyarn engaging means, is substantially prevented.

3. A tensioning device for yarn or the like travelling in the directionof its length under tension imposed upon it in its forward portion,which comprises a first means for engaging the yarn in its travel andfor imposing a substantial retarding force thereon, and a second meansimmediately forward of the first yarn engaging means but spaced asubstantial distance therefrom for engaging the yarn issuing from. thefirst yarn engaging means, the second yarn engaging means comprising amember having a smoothly curved yarn receiving and conducting passagetherethrough of such curvature that the yarn passing through the passageis substantially diverted from a straight path of travel, so that travelof twist in the yarn, imparted to the yarn at a location forward of thecurved passage, into the span of the yarn between the rst and secondyarn engaging means, is substantially prevented.

4. A tensioning device for yarn or the like travelling in the directionof its length under tension imposed upon it in its forward portion,which comprises a first means for engaging and com- 7 pressing the yarnin its travel and thus imposing a subtantial retarding force thereon,and a second means immediately forward of the first yarn engaging meansbut spaced a substantial distance therefrom for engaging the yarnissuing from the rst yarn engaging means, the second yarn engaging meanscomprising a member having a smoothly curved yarn receiving andconducting passage therethrough, an intermediate portion of which is ofshallow U-shaped curvature, the curvature of the passage being such`that the yarn passing through the passage is subjected to but a smallretarding force as a result thereof but is substantially diverted from astraight path of travel so that travel of twist in the yarn, imparted tothe yarn at a location forward of the curved passage, into the span ofthe yarn between the first and second yarn engaging means, issubstantially prevented.

5. A tensioning device for yarn or the like travelling in the directionof its length under tension imposed upon it in its forward portion,which comprises a first means for engaging the yarn in its travel andfor imposing a substantial retarding force thereon, such first meanscomprising a first member, said first memberV having an aperturetherethrough, at least a portion of the wall of the aperture being inthe shape of a portion of a sphere and constituting a seat and a yarnengaging surface past which the yarn travels, a second member in theform of a sphere supported in the seat, the sphere being movable intoand away from the seat in the first member, the yarn being compressedbetween the seat and the sphere, and means to press the sphere into theseat, and a scond means immediately forward of the first yarn engagingmeans but spaced a substantial distance therefrom for engaging the yarnissuing from the rst yarn engaging means, the second yarn engaging meanscomprising a member having a smoothly curved yarn receiving andconducting passage therethrough, an intermediate portion of which is ofshallow U-shaped curvature, the curvature of the passage being such thatthe yarn passing through the passage is substantially diverted from astraight pathof travel so that travel of twist in the yarn, imparted tothe yarn at a location forward of the curved passage, into the span ofthe yarn between the first and second yarn engaging means, issubstantially prevented.

6. Apparatus for twisting elongated exible material such as yarn whichcomprises means engaging the forward portion of the yarn to impel theyarn under tension in the direction of its length through the twistingaparatus, a tension means engaging the yarn in its travel and imposing asubstantial lretarding force thereon, a yarn twisting guide forward ofthe tension means and receiving yarn therefrom, means to rotate thetwisting guide relative to the tension means,

and yarn engaging means positioned intermediate the tension means andthe twisting guide and immediately forward of the tension means, butspaced substantial distances from both the tension means and thetwisting guide, for substantially diverting the yarn issuing from thetension means from a straight line path of travel between the tensionmeans and the twisting guide, said last named yarn engaging means beingso constructed and arranged as substantially to prevent travel of thetwist in the yarn, imparted thereto by the twisting guide, into the spanof the yarn between the tension means and uch last named means.

7. Apparatus for twisting elongated nexlble material such as yarn whichcomprises driven means engaging the forward portion of the yarn to impelthe yarn under tension in the direction of its length through thetwisting apparatus, a tension means engaging the yarn in its travel andimposing a substantial retarding force thereon, a yarn twisting guideforward of the tension means and receiving yarn therefrom, means torotate the twisting guide relative to the tension means, and yarnengaging means positioned intermediate the tension means and thetwisting guide and immediately forward of the tension means, but spacedsubstantial distances from both the tension means and the twistingguide, for substantially diverting the yarn issuing from the tensionmeans from a straight line path of travel between the tension means andthe twisting guide, whereby substantially to prevent travel of the twistin the yarn, imparted thereto by the twisting guide, into the span ofthe yarn between the tension means and such last named means, the lastnamed means comprising a member having a smoothly curved yarn receivingand conducting passage therethrough, an intermediate portion of which isof shallow U-shaped curvature.

8. Apparatus for twisting elongated exible material such as yarn whichvcomprises driven means engaging the forward portion of the yarn to impelthe yarn in the direction of its length through the twisting apparatusunder tension, a tension means engaging the yarn in its travel andimposing a substantial retarding force thereon, said tension meanscomprising a rst member, said first member having an aperturetherethrough, at least a portion of the Wall of the aperture being inthe shape of a portion of a sphere and constituting a seat and a yarnengaging surface past which the yarn travels, a second member in theform of a sphere supported in the seat, the sphere being movable intoand away from the seat in the first member, the yarn being compressedbetween the seat and the sphere, and means to press the sphere into theseat, a .varn twisting guide forward of the tension means and receivingyarn therefrom, means to rotate the twisting guide relative to thetension means, and yarnvengaging means positioned intermediate thetension means and the twisting guide and immediately forward cf thetension means but spaced substantial distances from both the tensionmeans and the twisting guide for substantially diverting the yarnissuing from the tension means from a straight line path of travelbetween the tension means and the twisting guide, whereby substantiallyto prevent travel of the twist in the yarn, imparted thereto by thetwisting guide, into the span of the yarn between the tension means andsuch last named means, the last named means comprising a member having asmoothly curved yarn receiving and conducting passage therethrough, anintermediate portion of which is of shallow U-shaped curvature.

9. The method of twisting elongated flexible material such as yarn orthe like consisting at least largely of a plurality of individualcontinuous nlaments lying generally parallel to each.

other in the direction of the length of the yarn, which comprisesfeeding such yarn in the direction of its length in a zone ofsubstantiallength, within such zone performing on the yarn the followingsteps: impelling the yarn forwardly at the forward end of such zone,applying a retarding force to the yarn at the rear end of such zonewhereby the yarn is maintained under tension, feeding the yarn, from thelocation of application of the retarding force,in a straight line for anappreciable distance, at the end of such straight-line path divertingthe yarn markedly from a straight line by engagement of the yarn by adiverting member, restoring the yarn in its travel, at a locationforward of such diversion, to a path generally parallel to-that betweenthe points of application of the retarding force and of the diversion,and twisting the yarn at a location forward of its restoration to astraight line path of travel by rotating its forward portion about itslongitudinal axis relative to its portion rearwardly of the point ofdiversion, the tension Ain the yarn and its path of travel during suchdiversion being such that travel of the twist in the yarn into the spanof the yarn between the points of application of the retarding force andof the diversion is substantially prevented, whereby the filaments mayrealign themselves under tension into substantially parallelrelationship after being subjected to the retarding force and beforebeing twisted together.

10. The method of twisting elongated flexible material such as yarn orthe like consisting at least largely of a plurality of individualcontinuous filaments lying generally parallel to each other in thedirection of the length of the yarn, which comprises feeding such yarnin the direction of its length in a zone of substantial length, withinsuch zone performing on the yarn v the following steps: impelling theyarn forwardly at the forward end of such zone, applying a retardingforce to the yarn at the rear end of such zone by compressing the yarnbetween yarn engaging members whereby the yarn is maintained undertension, feeding the yarn from the location of application of theretarding force in a straight line for an appreciable distance, at theend of such straight-line path diverting the yarn markedly from astraight line by engagement of the yarn by a smoothly curved divertingmember,'restoring the yarn in its travel, at a location forward of suchdiversion, to a path generally parallel to that between the points ofapplication of the retarding force and of the diversion, and twistingthe yarn at a location forward of its restoration to a`straight linepath of travel by rotating its forward portion about its longitudinalaxis relative to its portion rearwardly of the point of diversion, thetension in the yarn at the location of its diversion and its path oftravel during such diversion being such that travel of the twist in' theyarn into the span of the yarn between the points of application of theretarding force and ofthe diversion is substantially prevented, theengagement between the yarn and the smoothly curved diverting memberbeing such as to impose a primarily circumferential force on the yarnwhile not adding materially to the tension in the yarn, whereby thefilaments may realign themselves under tension into substantiallyparallel relationship after being subjected to the retarding force andbefore being twisted together.

11. 'I'he method of twisting elongated flexible material such as yarn orthe like consisting at least largely of a plurality of individualcontinuous filaments lying generally parallel to each other in thedirection of the length of the yarn, which comprises feeding such yarnin the direction of its length in a zone of substantial length, withinsuch zone performing on the yarn the following steps: impelling the yarnforwardly at the forward end of such zone, applying a retarding force tothe yarn at the rear end of such zoneby compressing the yarn betweenyarn engaging members whereby the yarn is maintained under tension,feeding the yarn from the location of application of the retarding forcein a straight line for an appreciable distance, at the end of suchstraight-line path diverting the yarn markedly from a straight line byengagement of the yarn with a member having a yarn receiving andconducting passage in the shape of a U curve restoring the yarn in itstravel, at a location forward of such diversion, `to a path generallyparallel to that between the points of application of the retardingforce and of the diversion, and twisting the yarn at a location forwardof its restorationto a straightline path of travel by rotating itsforward portion about its longitudinal axis relative to its portionrearwardly of the point of diversion, the depth of the U-shaped curve ofdiversion and the tension in the yarn at the location of its diversionbeing such that .travel of the twist in the yarn into the span of theyarn between the points of application of the retarding force and of thediversion is substantially prevented, whereby the filaments may realignthemselves under tension into substantially .parallel relationship afterbeing subjected to the retarding force and before being twistedtogether.

12. Apparatus for twisting elongated flexible material such as yarnwhich comprises driven means engaging the forward portion of the yarn toimpel the yarn under tension in the direction of its length through thetwisting apparatus, a tension means engaging the yarn in its travel andimposing a substantial retarding force thereon, a yarn twisting guideforward of the tension means and receiving yarn therefrom, means torotate the twisting guide relative to the tension means, and yarnengaging means positioned inf termediate the tension means and thetwisting ing guide, whereby' substantially to prevent travel v of thetwist in the yarn, imparted thereto by the twisting guide, into the spanof the yarn between the tension means and such last named' means, thelast named means comprising a member having a smoothly curved yarnreceiving and conducting surface.

13. A tensioning device for yarn or the like travelling in the directionof its length under tension imposed upon it in its forward portion,which comprises means for engaging the yarn in its travel and forimposing a substantial retarding force thereon, and means immediatelyforward of the yarn engaging means but spaced a substantial distancetherefrom for substantially diverting the yarn issuing from the yarnengaging means from a straight line path of travel, the last named meanscomprising a yarn guiding roller journalled on an axis substantially atright angles to the path of travel of the yarn from the yarn engagingmeans, yarn issuing from the yarn engaging means being guided around theroller in contact with a substantial angular extent of the roller, suchroller substantially preventing travel of twist in the yarn, imparted tothe yarn at a location immediately forward of the yarn diverting means,into the span of the yarn be- 1l tween the yarn engaging means and theyarn diverting means.

14. Apparatus for twisting elongated flexible material such as yarnwhich comprises means engaging the forward portion of the yarn to impelthe yarn under tension in the direction of its length through thetwisting apparatus, a tension means engaging the yarn in its travel andimposing a substantial retarding force thereon, a yarn twisting guideforward of the tension means and receiving yarn therefrom, means torotate ithe twisting guide relative to the tension means,

and yarn engaging means positioned intermediate the tension means andthe twisting guide and immediately forward of the tension means, butspaced substantial distances from both the tension means and thetwisting guide, for substantially diverting the yarn issuing from thetension means from a straight line path of travel between the tensionmeans and the twisting guide, said last named yarn engaging meanscomprising a yarn guiding roller journalled on an axis substantially atright angles to the path of travel of the yarn from the yarn engagingmeans, yarn issuing from the yarn engaging means being guided around theroller in contact with a substantial angular extent of the roller, suchroller substantially preventing travel of the twist in the yarn,imparted thereto by the twisting guide,

into the span of the yarn between the tension a means and such lastnamed means.

15. Apparatus for twisting elongatedA fiexible material such as yarnwhich comprises driven means engaging the forward portion of the yarn toimpel the yarn under tension in the direction of its length through thetwisting apparatus, a tension means engaging the yarn in its travel andimposing a substantial retarding force thereon,

a yarn twisting guide forward of the tension means and receiving yarntherefrom, means to rotate the twisting guide relative to the tensionmeans, and yarn engaging means positioned intermediate the tension meansand the twisting guide and immediately forward of the tension means, butspaced substantial distances from both the tension means and thetwisting guide, for substantially diverting the yarn issuing from thetension means from a straight line path of travel between the tensionmeans and the twisting guide, whereby substantially to prevent travel ofthe twist in the yarn, imparted thereto by the twisting guide, into thespan of the` yarn between the tension means and such last named means,the last named means comprising a yarn guiding roller journalled. on anaxis substantially at right angles to the path of travel of the yarnfrom the yarn engaging means, yarn issuing from the yarn engaging meansbeing guided around the roller in contact with a substantial angularextent of the roller, 4

VINCENT A. AGRESTI.

GEORGE W. BOGDANFFY.

CLYDE O. MITCHELL.

HENRY C. UHLIG.

REFERENCES CITED The following references are of record in the le ofthis patent:

UNITED STATES PATENTS

